Beyond the Flat Spot: The Neurodevelopmental Story Behind Plagiocephaly
That flat spot on the back of your baby's head? It isn't the problem. It's the sign to look deeper. One in five babies in the developed world will develop a measurable flattening of the cranium in the first six months of life. Most parents are reassured that it's cosmetic and will round itself out on its own. But a decade of longitudinal research is telling a very different story — and it's important for mothers to be aware of this.
In this episode, Dr. Lisa unpacks what plagiocephaly actually is, why we're seeing so much more of it than we used to, the pregnancy-stage risk factors most parents are never told about, what the research from Seattle Children's is now showing about long-term cognitive and motor outcomes — and exactly what to do about it at every stage, from pregnancy through your child's first year and beyond.
Plagiocephaly — often called "flat head syndrome" — is one of the most misunderstood conditions of the first year of life. The conventional conversation focuses almost entirely on how the head looks. But the head shape isn't the issue. It's the visible flag for what's happening underneath in the developing nervous system.
Drawing on 23 years of clinical experience working with babies and children, Dr. Lisa walks through the functional-neurology lens on plagiocephaly: what causes it, why the rates have exploded since the 1990s, what the research now tells us about long-term developmental outcomes, and the four pieces of an integrated standard of care.
This is the conversation parents need to be having — and the kind of clear, root-cause information that helps mothers stop guessing and start leading.
• Mothers who are pregnant and want to be proactive about their baby's neurodevelopment from before birth.
• Parents who have noticed (or been told about) a flattening on the back of their baby's head and aren't sure what to do.
• Mothers whose baby has a strong head-turning preference, torticollis, or has had an assisted delivery. • Parents who have been reassured that "it will round out on its own" — and want to understand the full picture.
• Anyone who wants to understand the neurological story behind a visible symptom, instead of waiting for a diagnosis.
• Health-conscious mothers who think in terms of root cause, optimal development, and prevention rather than wait-and-see.
• A clear, plain-language understanding of what plagiocephaly is, the difference between deformational plagiocephaly and craniosynostosis, and what's actually happening in the skull.
• The five pregnancy- and birth-stage risk factors that the research consistently links to plagiocephaly — including the one most parents are never told about.
• Why the 1992 "Back to Sleep" recommendation, while life-saving for SIDS, is part of why we're now seeing a 5–6× rise in plagiocephaly.
• What the longitudinal research from Seattle Children's Research Institute (Dr. Matthew Speltz and colleagues) shows about long-term motor, cognitive, language, and behavioral outcomes.
• The integrated 4-piece standard of care: cervical and cranial assessment, repositioning and tummy time, pediatric chiropractic, and how to think about helmet therapy.
• An age-by-age action plan: what to do in pregnancy, the first 3 months, 3–6 months, and after 6 months.
• How to vet the practitioner you choose to assess your baby — and the question almost no one asks.
Episode Timestamps Use these to jump to the section you need. Times are approximate.
00:00 Welcome & why this is one of the most misunderstood conditions of the first year
01:30 What plagiocephaly actually is — and why the head shape is the alarm bell, not the issue
03:30 Two categories: craniosynostosis vs. deformational plagiocephaly
05:00 Why a baby's skull is designed to deform (and what brachycephaly means)
06:30 The numbers: 1 in 5 babies — the New Zealand prospective cohort study
07:30 A brief history: the 1992 "Back to Sleep" recommendation and the unintended consequence
09:30 How container culture and reduced tummy time changed the modern baby's mechanical environment
12:00 Risk factor #1 (begins in pregnancy): uterine constraint
13:30 Risk factor #2: breech and transverse position
14:00 Risk factor #3: torticollis — and why traditional stretching often falls short
17:30 Risk factors #4 & #5: assisted delivery and prematurity
18:30 Practical guidance during pregnancy: movement, alignment, and finding the right practitioner
19:30 The question you should always ask your healthcare provider — and why almost nobody does
21:30 Why "wait and see" falls short: introducing the Seattle Children's research
23:00 What the Bayley Scales of Infant Development showed at 6 months — and why a 1 SD gap matters
24:30 The 18-month, 36-month, and school-age follow-ups (Journal of Pediatrics 2019 & 2022)
27:00 Plagiocephaly as a marker — not a cause — of underlying neuromotor patterns
28:30 The integrated standard of care: four pieces
29:30 Piece 1: Cervical spine and cranial base assessment
30:30 Piece 2: Repositioning, tummy time, and why a little frustration is the engine of development
33:30 Piece 3: Pediatric chiropractic — what it actually looks like and the 2020 evidence synthesis
35:30 Piece 4: Helmet therapy — when, why, and the questions to ask
37:00 Your action plan during pregnancy
38:30 Your action plan: 0–3 months
39:30 Your action plan: 3–6 months
41:00 Your action plan: after 6 months — the window is not closed
41:30 Closing: plagiocephaly as a window into the nervous system
The head shape is the alarm bell, not the diagnosis Plagiocephaly is the visible flattening you can see — but the meaningful clinical question is what's happening underneath. The asymmetry is almost always the downstream effect of an underlying neuromotor pattern: limited cervical mobility, asymmetric tone, retained primitive reflexes, or a baby who isn't moving spontaneously and symmetrically. Treat the head as a window, not a wall.
Why we're seeing more of it;
Three converging factors have made plagiocephaly far more common in the last 30 years: (1) the 1992 "Back to Sleep" recommendation that dramatically reduced SIDS but also kept babies on the same surface for far more hours per day, (2) the rise of container culture — car seats, bouncers, swings, rockers — which holds the back of the head against a hard surface for hours, and (3) a sharp drop in the amount of focused tummy time modern babies experience in their first months of life.
The five risk factors that begin in pregnancy;
• Uterine constraint — first pregnancies, twins/triplets, fibroids, low amniotic fluid, or an unusually shaped uterus that limits baby's ability to move and rotate.
• Breech or transverse position — when baby's head is wedged into one corner of the uterus or pelvis for weeks before birth.
• Torticollis — tightness or imbalance of the SCM muscles, often paired with cervical spine restrictions, that creates a strong head-turning preference. Limited passive neck rotation at birth is one of the strongest predictors of plagiocephaly developing in the first six weeks of life.
• Assisted delivery — vacuum extraction, forceps, or prolonged second stage labor that leaves cervical restrictions that can persist for weeks or months.
• Prematurity — softer, more pliable skulls for a longer window, often paired with extended time on hard NICU surfaces.
What the long-term research is telling us;
Dr. Matthew Speltz and colleagues at Seattle Children's Research Institute and the University of Washington enrolled 472 babies — 235 with deformational plagiocephaly and 237 demographically matched controls — and followed them prospectively from infancy through school age. At 6 months, the babies with plagiocephaly scored lower than controls on every Bayley Scales subscale (cognitive, language, motor), with the largest gap in motor function (roughly one full standard deviation below). At 18 and 36 months, the motor gap narrowed but the cognitive and language gaps became more pronounced. At school age, mildly affected children had largely caught up, but moderately and severely affected children continued to score lower on cognition and academic achievement. A clear dose-response pattern emerged: the more severe the early plagiocephaly, the larger the school-age gap. A follow-up paper in 2022 found modestly elevated rates of behavioral and social functioning concerns in the moderate and severe groups.
The integrated standard of care — four pieces;
• Assess the cervical spine and cranial base. Every baby with plagiocephaly should have a careful, hands-on evaluation of cervical mobility, cranial base function, and the soft tissues of the neck and shoulders. If your baby cannot turn their head equally to both sides, no amount of repositioning is going to solve the problem.
• Repositioning and tummy time. Significant, daily, awake-time tummy time from the very first weeks of life. Vary the side baby's head sits on the changing table, the arm you carry them on, the side they feed from. Bring back the variability the developing nervous system needs.
• Pediatric chiropractic care when indicated. A 2020 synthesis in the Journal of Chiropractic and Manual Therapies found manual therapy approaches stood out among conservative interventions. Pediatric chiropractic is not a smaller version of adult care — the forces used are a fraction of an adult adjustment, comparable to the pressure you'd use on your own eyeball or a ripe tomato.
The single most important reframe;
Plagiocephaly is not a cosmetic problem. It is a neurodevelopmental signal. And in 2026, the standard of care has to meet that signal with the depth of response it deserves.
Free Resources & Mentioned in This Episode
• Dr. Lisa's Substack — free weekly articles that go deeper on the topics covered on the podcast. https://drlisapedersen.substack.com/
• The 8 Pillars of Thriving Health Masterclass — Dr. Lisa's 90-minute deep dive on the foundations of building thriving health in babies and children.
https://www.createthrivingfamilies.com/foundations-masterclass-thriving-during-the-first-5-years-1
Studies, Books & Researchers Cited
A complete reference list for further reading. Peer-reviewed research;
Hutchison BL, Hutchison LAD, Thompson JMD, Mitchell EA. "Plagiocephaly and Brachycephaly in the First Two Years of Life: A Prospective Cohort Study." Pediatrics, 2004; 114(4): 970–980. (The New Zealand cohort study cited in the episode — 200 healthy full-term babies followed from birth.)
Collett BR, Wallace ER, Kartin D, Cunningham ML, Speltz ML. "Cognitive Outcomes and Positional Plagiocephaly." Pediatrics, 2019; 143(2): e20182373. (The Seattle Children's longitudinal study — school-age cognitive outcomes.)
Collett BR, Wallace ER, Kartin D, Speltz ML. "Behavioral and Social Functioning in Children with Deformational Plagiocephaly: Outcomes Through School Age." Journal of Developmental & Behavioral Pediatrics, 2022. (Follow-up paper on behavioral and social outcomes.)
Collett B, Breiger D, King D, Cunningham M, Speltz M. "Neurodevelopmental Implications of "Deformational" Plagiocephaly." Journal of Developmental & Behavioral Pediatrics, 2005; 26(5): 379–389. (Earlier foundational work from the Seattle group.)
American Academy of Pediatrics Task Force on Infant Positioning and SIDS. "Positioning and SIDS." Pediatrics, 1992; 89(6): 1120–1126. (The original "Back to Sleep" recommendation.)
Driehuis F, Hoogeboom TJ, Nijhuis-van der Sanden MWG, et al. "Spinal Manual Therapy in Infants, Children and Adolescents: A Systematic Review." PLOS ONE / Chiropractic & Manual Therapies, 2019–2020. (Representative of the 2020 evidence synthesis cited in the episode.)
Bayley N. Bayley Scales of Infant and Toddler Development (3rd or 4th ed.). The standardized infant developmental assessment used in the Speltz studies.
Foundational textbooks & clinical authors
Anrig C, Plaugher G. Pediatric Chiropractic. Wolters Kluwer / Lippincott Williams & Wilkins. The standard reference text for chiropractic care of infants and children.
Fysh P. Chiropractic Care for the Pediatric Patient. International Chiropractors Association. A foundational pediatric clinical text.
Miller J. Evidence-Based Chiropractic Care for Infants: Rationale, Therapies, and Outcomes. Praeclarus Press. Dr. Joyce Miller's body of work at the Anglo-European College of Chiropractic / Bournemouth University on pediatric outcomes.
Website: createthrivingfamilies.com
Instagram: @dr.lisapedersen
Substack: substack.com/@drlisapedersen
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Original music composed by Philippe Custeau
This podcast is for educational purposes only and does not constitute medical or professional advice. Always consult a qualified healthcare provider with questions about your child's health and development.
